Phylogenetic studies of the genus <Emphasis Type="Italic">Cebus</Emphasis>(Cebidae-Primates) using chromosome painting and G-banding

Background  

Chromosomal painting, using whole chromosome probes from humans and Saguinus oedipus, was used to establish karyotypic divergence among species of the genus Cebus, including C. olivaceus, C. albifrons, C. apella robustus and C. apella paraguayanus. Cytogenetic studies suggested that the species of this genus have conservative karyotypes, with diploid numbers ranging from 2n = 52 to 2n = 54.     

Evolutionary experimentation through hybridization under laboratory condition in <Emphasis Type="Italic">Drosophila</Emphasis>: Evidence for Recombinational Speciation

Background  

Drosophila nasuta nasuta (2n = 8) and Drosophila nasuta albomicans (2n = 6) are a pair of sibling allopatric chromosomal cross-fertile races of the nasuta subgroup of immigrans species group of Drosophila. Interracial hybridization between these two races has given rise to new karyotypic strains called Cytorace 1 and Cytorace 2 (first phase). Further hybridization between Thailand strain of D. n. albomicans and D. n. nasuta of Coorg strain has resulted in the evolution of two more Cytoraces, namely Cytorace 3 and Cytorace 4 (second phase). The third phase Cytoraces (Cytorace 5 to Cytorace 16) have evolved through interracial hybridization among first, second phase Cytoraces along with parental races. Each of these Cytoraces is composed of recombined genomes of the parental races. Here, we have made an attempt to systematically assess the impact of hybridization on karyotypes, morphometric and life history traits in all 16 Cytoraces.     

Different rate of intrapopulation chromosome polymorphism in two species of Black Sea Blennies (Blenniidae,Pisces)

Somatic karyotypes in seven specimens of Blennius sanguinolentus include 22 subtelocentric and 26 acrocentric chromosomes, whereas one male has 2n=47=1M+22ST+24A: polymorphism is evidently a result of centric fusion of two acrocentrics. Blennius tentacularis is characterized by the availability of four karyomorphs out of which three coincide with karyotypes described earlier (Carbone et al., 1987). Karyttype-I consists of a 48 small uni-armed chromosome, but both karyotypes II and III with 2n=48 and 2n=47 respectively include one large acrocentric chromosome, and karyotype-IV has one large submetacentric out of the 47 chromosomes. Karyotypic variability of B. tentacularis is attributed either to polymorphism by 1–3 chromosome rearrangements or to availability of sex-determining mechanism, including the Y-autosome translocation. This diverse series of male karyomorphs may reflect the complicated behavioural structure.     

Genotypic and phenotypic properties of <Emphasis Type="Italic">Candida parapsilosis</Emphasis><Emphasis Type="Italic">sensu strictu</Emphasis> strains isolated from different geographic regions and body sites

Background  

Candida parapsilosis is known to show limited genetic variability, despite different karyotypes and phenotypes have been described. To further investigate this aspect, a collection of 62 sensu strictu C. parapsilosis independent isolates from 4 geographic regions (Italy, n = 19; New Zealand, n = 15; Argentina, n = 14; and Hungary, n = 14) and different body sites (superficial and deep seated) were analysed for their genetic and phenotypic traits. Amplification fragment length polymorphism (AFLP) analysis was used to confirm species identification and to evaluate intraspecific genetic variability. Phenotypic characterisation included clinically relevant traits, such as drug susceptibility, in vitro biofilm formation and aspartyl protease secretion.     

The cytogenetic structure of Vicia sativa aggregate

Summary The cytogenetic structure of Vicia sativa aneuploid series was assessed by examination of the chromosome pairing in hybrids between types having 2n = 10, 2n = 12 and 2n = 14. Two different karyotypes were distinguished at both the 2n = 10 and 2n = 12 levels. Chromosome pairing in hybrids involved two 2n = 10 karyotypes, indicating that the parental lines differed by two translocations. A similar indication was obtained for the two 2n = 12 karyotypes employed. The meiotic behavior of the 2n = 10 x 2n = 12 hybrids indicated that the parental lines differed by up to three translocations, some of which involved unequal chromosome segments. It has been proposed that the 2n = 10 types were developed from the 2n = 12 via centric or tandem fusion and additional rearrangements further accelerated chromosome repatterning at the two 2n levels. Hybrids between the 2n = 14 V. sativa and the former 2n types had very irregular chromosome pairing and were highly sterile. It has been proposed that the 2n = 14 type is a relatively new evolvement in V. sativa because of its shorter complement in comparison with the other karyotypes. The subterraneous pods of the 2n = 14 type, a characteristic which is absent in other V. sativa types and in the entire genus Vicia, also supports an advanced, phylogenetic position. The 2n = 14 type probably arose from n = 7 gametes produced by the 2n= 12 x 2n = 10 hybrid and the establishment of the row 2n = 14 type was acquired through conspicuous chromosome deletions. In spite of its remarkable chromosomal variation, V. sativa can still be considered, for breeding purposes, as being one gene pool. The wild forms of V. sativa can thus be valuable sources for improving the cultivated vetch.     

QTL mapping of agronomic traits in tef [<Emphasis Type="Italic">Eragrostis tef</Emphasis>(Zucc) Trotter]

Background  

Tef [Eragrostis tef (Zucc.) Trotter] is the major cereal crop in Ethiopia. Tef is an allotetraploid with a base chromosome number of 10 (2n = 4× = 40) and a genome size of 730 Mbp. The goal of this study was to identify agronomically important quantitative trait loci (QTL) using recombinant inbred lines (RIL) derived from an inter-specific cross between E. tef and E. pilosa (30-5).     

Chromosome spreading of associated transposable elements and ribosomal DNA in the fish Erythrinus erythrinus. Implications for genome change and karyoevolution in fish

Background  

The fish, Erythrinus erythrinus, shows an interpopulation diversity, with four karyomorphs differing by chromosomal number, chromosomal morphology and heteromorphic sex chromosomes. Karyomorph A has a diploid number of 2n = 54 and does not have differentiated sex chromosomes. Karyomorph D has 2n = 52 chromosomes in females and 2n = 51 in males, and it is most likely derived from karyomorph A by the differentiation of a multiple X₁X₂Y sex chromosome system. In this study, we analyzed karyomorphs A and D by means of cytogenetic approaches to evaluate their evolutionary relationship.     

Chromosome translocations in the karyotypes of wild boars Sus scrofa L. of the European and the Asian areas of USSR

Summary The karyotypes of the 80 wild boars of the four subspecies, Sus scrofa ussuricus Heude from the Far East of USSR, S. s. nigripes Blanf. from Kirghizia (the Middle Asia), S. s. attila Thos. from Azerbaijan, S. s. ferus from Lithuania, Byelorussia and Central Russia, and the 44 domestic pigs of the five different breeds (Vietnamese Black, Siberian Omskaja Gray, Kakhethian-aborigen Georgian, Mangalica Hungarian, Landrace Swedish), were studied by the Giemsa Banding Method. Differential staining by the G-Method made it possible to identify all the homologous chromosomes of the wild and domestic pig karyotypes as well as to reveal the polymorphism of wild boar karyotypes (2n = 36, 37 and 38), which are determined by the two types of chromosome translocation. Crosses between domestic pigs (2n = 38) and wild boars (2n = 36 and 37) with different chromosome rearrangements might help to clarify the genetic function of the chromosomes A4, B3, B4, B5 and allow their use as genetic markers.     

Chromosome localization and gene synteny of the major histocompatibility complex in the owl monkey,Aotus

Rodent cells were hybridized with owl monkey (Aotus) cells of karyotypes II, III, V, and VI. Aotus-rodent somatic hybrid lines preferentially segregating Aotus chromosomes were selected to determine the chromosomal location of the major histocompatibility complex and other genes with which it is syntenic in man. Based on correlation between concordant segregation of the chromosome as visualized by G-banding and expression of the Aotus antigens or enzymes in independent Aotus-rodent hybrid clones, we have assigned Aotus gene loci for the MHC, GLO, ME₁, SOD₂, and PGM₃ to Aotus chromosome 9 of karyotype VI (2n=49/50), chromosome 10 of karyotype V (2n=46), and chromosome 7 of karyotypes II and III (2n = 54 and 53). On the basis of banding patterns we previously postulated that these chromosomes of the different karyotypes were homologous. The gene assignments reported here provide independent evidence for that hypothesis. Aotus chromosomes 9 (K-VI), 10 (K-V), and 7 (K-II, III) are homologous to human chromosome 6 in that they all code for the MHC, GLO, ME₁, SOD₂, and PGM₃. The structural differences between these homologous chromosomes probably resulted from a pericentric inversion.Abbreviations used in this paper MHC major histocompatibility complex - HLA human lymphocyte antigen - PGM3 phosphoglucomutase-3 - ME₁ cytoplasmic malic enzyme-1 - SOD₂ superoxide dismutase-B - GLO glyoxalase 1 - OMLA owl monkey leukocyte antigens - K karyotype - ₂-M ₂-microglobulin - DMEM Dulbecco's modification of Eagle's medium - PEG polyethylene glycol - HAT hypoxanthine, aminopterin, and thymidine - KC1 potassium chloride - G-band-trypsin Giemsa band     

Chromosomal plasticity and evolutionary potential in the malaria vector <Emphasis Type="Italic">Anopheles gambiae</Emphasis> sensu stricto: insights from three decades of rare paracentric inversions

Background  

In the Anopheles gambiae complex, paracentric chromosomal inversions are non-randomly distributed along the complement: 18/31 (58%) of common polymorphic inversions are on chromosome arm 2R, which represents only ~30% of the complement. Moreover, in An. gambiae sensu stricto, 6/7 common polymorphic inversions occur on 2R. Most of these inversions are considered markers of ecological adaptation that increase the fitness of the carriers of alternative karyotypes in contrasting habitats. However, little is known about the evolutionary forces responsible for their origin and subsequent establishment in field populations.     

Natural killer,natural killer T,helper and cytotoxic T cells in the decidua from recurrent spontaneous abortion with normal and abnormal chromosome karyotypes

Problem

Recurrent spontaneous abortion (RSA) is associated with immune imbalance at the maternal–fetal interface. Decidual immune cells and cytokines expressed at this interface regulate the response of the maternal immune system to the fetus. However, the populations and cytokine expression levels of these lymphocytes in miscarriage with normal and abnormal chromosome karyotypes remain unclear.

Polyploidy and aneuploidy inOphrys,Orchis, andAnacamptis (Orchidaceae)

Studies on chromosome numbers and karyotypes in Orchid taxa from Apulia (Italy) revealed triploid complements inOphrys tenthredinifera andOrchis italica. InO. tenthredinifera there is no significant difference between the diploid and the triploid karyotypes. The tetraploid cytotype ofAnacamptis pyramidalis forms 36 bivalents during metaphase I in embryo sac mother cells. Aneuploidy was noticed inOphrys bertolonii ×O. tarentina with chromosome numbers n = 19 and 2n = 38. There were diploid (2n = 2x = 36), tetraploid (2n = 4x = 72), hexaploid (2n = 6x = 108) and octoploid (2n = 8x = 144) cells in the ovary wall of the diploid hybridOphrys apulica ×O. bombyliflora. Evolutionary trends inOphrys andOrchis chromosomes are discussed.     

Island species radiation and karyotypic stasis in <Emphasis Type="Italic">Pachycladon</Emphasis>allopolyploids

Background  

Pachycladon (Brassicaceae, tribe Camelineae) is a monophyletic genus of ten morphologically and ecogeographically differentiated, and presumably allopolyploid species occurring in the South Island of New Zealand and in Tasmania. All Pachycladon species possess ten chromosome pairs (2n = 20). The feasibility of comparative chromosome painting (CCP) in crucifer species allows the origin and genome evolution in this genus to be elucidated. We focus on the origin and genome evolution of Pachycladon as well as on its genomic relationship to other crucifer species, particularly to the allopolyploid Australian Camelineae taxa. As species radiation on islands is usually characterized by chromosomal stasis, i.e. uniformity of chromosome numbers/ploidy levels, the role of major karyotypic reshuffling during the island adaptive and species radiation in Pachycladon is investigated through whole-genome CCP analysis.     

Minichromosome stability induced by partial genome duplication in Arabidopsis thaliana

Two partially reconstructed karyotypes (RK1 and RK2) of Arabidopsis thaliana have been established from a transformant, in which four structurally changed chromosomes (α, β, γ, and δ) were involved. Both karyotypes are composed of 12 chromosomes, 2n = 1￠￠+ 3￠￠+ 4￠￠+ 5￠￠+ a￠￠+ g￠￠ = 12 {2}n = {1}\prime \prime + {3}\prime \prime + {4}\prime \prime + {5}\prime \prime + \alpha \prime \prime + \gamma \prime \prime = {12} for RK1 and 2n = 3￠￠+ 4￠￠+ 5￠￠+ a￠￠+ b￠￠+ g￠￠ = 12 {2}n = {3}\prime \prime + {4}\prime \prime + {5}\prime \prime + \alpha \prime \prime + \beta \prime \prime + \gamma \prime \prime = {12} for RK2, and these chromosome constitutions were relatively stable at least for three generations. Pairing at meiosis was limited to the homologues (1, 3, 4, 5, α, β, or γ), and no pairing occurred among non-homologous chromosomes in both karyotypes. For minichromosome α (mini α), precocious separation at metaphase I was frequently observed in RK2, as found for other minichromosomes, but was rare in RK1. This stable paring of mini α was possibly caused by duplication of the terminal tip of chromosome 1 that is characteristic of RK1.     

High-resolution flow karyotyping and chromosome sorting in Vicia faba lines with standard and reconstructed karyotypes

Flow cytometric analysis has been performed on chromosomes isolated from formaldehyde-fixed root tips in a Vicia faba (2n = 12) line with a standard (wild-type) karyotype and in six V. faba translocation lines with reconstructed karyotypes. The resolution of individual chromosome types on histograms of chromosome fluorescence intensity (flow karyotypes) depended on the type of fluorochrome used for chromosome staining. The highest degree of resolution was achieved with 4,6-diamidino-2-phenylindole (DAPI). The lower resolution obtained after staining with mithramycin A (MIT) and propidium iodide (PI) was probably due to the sensitivity of these stains to changes in chromatin structure induced by formaldehyde fixation. After the staining with DAPI, only 1 chromosome type could be discriminated in the line with a standard karyotype. In the translocation lines, the number of chromosome types resolved on flow karyotypes ranged from 2 in the G and the ACB lines to all (6) chromosome types in the EFK and EF lines. Refined flow karyotyping permitted the sorting of a total of 15 different chromosome types from five of the translocation lines. It is expected that flow sorting of chromosomes from reconstructed karyotypes will become a powerful tool in the study of nuclear genome organisation in V. faba.     

Cytogenetic studies of two land-planarian species from Brazil: Geoplana marginata and Issoca rezendei (Tricladida,Terricola)

The chromosome complement and the C-banded karyotypes of specimens of Geoplana marginata auct. and of Issoca rezendei (Schirch) were investigated. The diploid and fundamental numbers of the two species were identical (2n = 14; FN = 28). Their karyotypes were similar except for the morphology of chromosome pair 6. Their C-banding patterns differed in quantity and localization of the constitutive heterochromatin. The similarity in karyotypes of these species support the hypothesis, proposed earlier on morphological grounds, that the genera Geoplana Stimpson and Issoca Froehlich are closely related. G. marginata and I. rezendei are the first land planarian species of the Neotropical Region to have their karyotypes described.     

Genetic studies in representatives of genusRhipidomys (Rodentia, Sigmodontinae) from Brazil

Karyotypic polymorphism of five taxa of the rodent genusRhipidomys from the Brazilian Amazon and Cerrado biomes was analysed.Rhipidomys nitela Thomas, 1901 from Amazon has 2n=48, FN=68. The other species, all have 2n=44, but can be separated into two groups, one with high FNs (76, 80) and the other with low FNs (48, 52). Two cytotypes ofR. mastacalis (Lund, 1840) with high FNs were trapped in four localities of the Cerrado, showing 19 and 17 biarmed autosomes, respectively. A low FN (48) was observed inR. leucodactylus (Tschudi, 1844) in two localities of the Cerrado and FN=52 in one locality in the Cerrado and the Amazon. All taxa with 2n=44 have a medium-sized acrocentric X chromosome and a small Y.Rhipidomys nitela is different from the species with 2n=44 by presenting a heterochromatic short arm of the X chromosome. In all karyotypes analysed, the nucleolus organizer regions were located in the short arms of two to six pairs and the (T₂AG₃)_n telomeric probes hybridizedin situ in both the short and long arms of all pairs of the karyotypes.     

Cytotaxonomy of Dubyaea glaucescens (Compositae–Cichorieae)

Recent molecular phylogenetic analyses indicate that Dubyaea glaucescens (Compositae–Cichorieae) should be transferred to the genus Faberia as F. glaucescens. Here, we present cytological evidence for this transfer. Dubyaea glaucescens comprises two ploidy levels, 2n = 34 (diploid) and 2n = 51 (triploid), making the basic chromosome number x = 17. The chromosomes vary in length from 5.82 μm to 2.11 μm, and the karyotypes are 2n = 20m + 14sm (3sat) for the diploid cytotype and 2n = 30m + 21sm (3sat) for the triploid cytotype. Karyological characters of D. glaucescens, including chromosome number, size, morphology, and karyotype asymmetry, all agree remarkably with those reported previously in Faberia, but are distinct from those in other species of Dubyaea. The transfer of D. glaucescens to Faberia is thus strongly corroborated.     

风毛菊属5种植物的核型分析

采用常规压片法,对风毛菊属(Saussurea)5种植物的染色体数目和核型类型进行分析。结果表明:大耳叶风毛菊(S.macrota)核型公式为2n=2x=26=10m+12sm+4st,属2A型;长梗风毛菊(S.dolichopoda)核型公式为2n=2x=26=14m+8sm+4st,属2A型;川陕风毛菊(S.licentiana)核型公式为2n=2x=28=12m+16sm,属2B型;杨叶风毛菊(S.populifolia)核型公式为2n=2x=28=6m+18sm+4st,属2B型;尾叶风毛菊(S.caudata)核型公式为2n=2x=30=14m+14sm+2st,属2A型。这5种风毛菊属植物中,除大耳叶风毛菊染色体数目和核型类型与前人报道的一致外,其余4种植物的染色体数目和核型类型均为首次报道,并在川陕风毛菊中发现1对B染色体。     

Comparative karyotype analysis in Haplopappus Cass. and Grindelia Willd. (Asteraceae) by double FISH with rRNA specific genes

The genera Grindelia Willd. and Haplopappus Cass. belong to the family Asteraceae - Astereae and are distributed in America and South America, respectively. Previous cytotaxonomic studies showed for South American species of Grindelia 2n=12 and for Haplopappus 2n=10 and 2n=12. Both Grindelia species (G. anethifolia, G. prunelloides), newly analyzed with molecular-cytological methods, exhibited symmetric karyotypes (AsI %=55.46 and 55.95) with metacentric chromosome sets (5m + 1m-sat) and 2n=12 chromosomes. The NOR was detected after fluorescence in situ hybridization (FISH) with 18/25S rDNA in the satellite chromosome 2. In contrast H. Happlopappus glutinosus, H. grindeloides and H. stolpii showed exclusively a higher asymmetric index (66.83%, 67.01% and 68.87%, respectively) with submetacentric chromosome sets (4sm + 1sm–sat). The sat-chromosomes 3 of H. glutinosus and H. grindelioides were both significantly different in their length from chromosomes 2 and 4. Furthermore in Grindelia the FISH with 5S rDNA could estimate signals in the short arms of chromosomes 3 or 4, that were not significantly differentiated in their length. Contrary to these findings in Grindelia, the position of 5S rDNA in Haplopappus was detected in the long arms of chromosome 1 (H. grindelioides and H. stolpii) and chromosome 2 (with two different loci) and chromosome 4 of H. glutinosus. The lengths of all measured chromosome arms with 5S rDNA were significantly different to those of the neighbours in the karyotypes. The two-color FISH of 5S and 18/25S rDNA had provided clear karyotypic markers for three (Haplopappus glutinosus) and two (H. grindelioides and H. stolpii) chromosomes. The number and position of rDNA signals were relatively highly conserved in the investigated five species without the double marked chromosome 2 of H. glutinosus, which shows an evolutionary dynamic of this 5S rRNA specific gene cluster. This investigation supports the assumption that the evolution of New World members of Grindelia and Haplopappus has not been accompanied by large karyotypic changes, but small chromosomal rearrangements have undoubtedly occurred (e.g. 5S rDNA localizations).